Kevin Michael

Alright , new problem seems I can't win! Having a bad idle and engine dying unless I nurse the throttle. I checked timing at idle it is almost on the 20. It is supposed to be on the ten!. My other s4 is 10 on the button at idle (675-700) rpm. The marks on the cams are spot-on and the belt is at proper tension, so how could my timing be so screwed? Before I start changing parts (ign. stgs. hall, knock sens. etc.) Does anyone know a common fault scenario?
Thanks, Kevin

Bill 86.5 928s

Kevin.....This sounds like a vacuum problem to me. I would look for a leak somewhere in your vacuum lines.....I hope this helps.Goodluck........Bill

Bill51sdr

Ignition timing is controlled by the LH. Hate to suggest this, but try swapping your other car's LH and see what happens. Is this the same car that soaked the plugs before?

Scott M.

Knock and Hall sensors take out timing, not add it. I second Bills recc. swap LH box.

Kevin Michael

Same car Bill. I think the last problem is related. Swapped lh back and forth between s4's. No changes. I am thinking of yanking the manifold, but I have a receipt from the po it was done 15000mi. ago. Should I pull the mani and take a look? the beast runs great when you take her out and plenty of power, just sounds a little off. Also clutching ,braking and trying to feather the throttle at stoplights are a challenge right now! Kevin

Kevin Michael

No body's s4 or later never had this problem? It is running 20 deg. instead of 10 at idle and everything is lining up fine. 0tdc and right on the marks no matter how many times you spin the engine. Blowing wet black out of the pipes , idling at 3-400rpms, wanting to cut-out after a rev. I miss my ob's!! They were simple.

John Speake

Hi Kevin,
When did this problem start ? Please give some history.

Does this S4 have the Autothority chips ???

Ignition advance at idle is controllled by the EZK ECU. It sets advance by a "load" signal it receives from the LH. This load signal effectively comes from the ammount of air the MAF is reading.

From what you describe, I think it sounds like the MAF has a problem.

Have you tried a MAF disconnect ?

Normy

Check your MAF/ adjust your mixture and see what happens. Sure your timing light is working right?

N!

Kevin Michael

John, Been going on since last year. That is why I ordered a new maf from you . I thought it was the culprit, but apparently not. I took the autothority chips out last month and it seems to act worse without them. Then I swapped Lh unit with my other 87(stock chips). that car runs perfectly, so I know the lh is ok. I get the same problem with the lh and ezk from the perfect running car, and that car runs perfect with the lh and ezk from the problem car. So I ruled out the maf and both computers as the culprit. What does that leave? Maybe the crank sensor? Normy, I wondered the same thing! I bought a brand new t-lite,just to be double sure. Oh well, now I have a back-up t-lite.

Kevin Michael

Anything else I should look at besides MAF and LH/EZK? Both are fine as I have a well running spare s4. If I can't solve , anyone interested in a nice 5 spd.s4 with a confusing timing issue?!!

Tom. M

I know you said the marks on the cams are right..but what about the relationship between the cams and the cam gears...might be time to pull the cam covers and check your cam timing/lift with a dial indicator.

My lift was off about about 100 thousandths..(don' t ask hahaha) ..and surprisingly the car ran..but ran with a slightly odd sound and power delivery.

Good luck...
Later,
Tom
89GT

Kevin Michael

UPDATE!!!!!
I did the MAF test as I said earlier (pull plug) and it did not run any better. So I assumed it was not the Maf as I purchased a rebuilt unit from JDS (John Speake) only 5-6 mos. ago. Guess what? For thoroughness sake I put my original Maf in and it fired immediately and idled very steady at 675-700rpm. No more unburnt fuel in the exhaust or smoke,no more cutting out, and it sounds very good. I am glad I kept my old one and ate the core charge. I bought the new Maf because it was part of the maintenence regimen for my car, and I was having a problem so I did a thorough tune-up including new everything. Apparently, one of the new parts I bought cured the problem but the rebuilt MAF unit I put in was bad and created almost the same problem. So in a nutshell I solved the original problem(probably coils) and didn't realise it because I installed the new Maf without testing the car with old one. I hope this makes sense. I am not faulting John Speake as he is a professional and an asset to this community, and I have heard that sometimes new or rebuilt parts are no good right out of the box. Kevin

macreel

Hmmm... I'd suspect the wiring harness/receptacle
based on this latest info. How do the pins look in
both the connector & receptacle ??

Glad you're running ok. Still offering up that S4 ?

G'luck.

Kevin Michael

Macreel, harness and receptacle on the car and both Mafs look very good. I thinking i'll keep her now, I just took her out for a rip, and it is running STRONG and it has the power it had last year before the initial problem! sweeeeeeeeeeeeet!
Kevin

Bill51sdr

Congrats Kevin, happy for you! Enjoy driving it!